Most sports shoes now include at least one shock-absorbing element placed in the heel part of the shoe, under the calcaneum. This shock-absorbing element is generally an independent element, with increased elasticity, placed inside the outer sole. However, it can nevertheless be incorporated into the said sole.
In document FR.2.438.983, the shock-absorbing element is located between the inner sole of the shoe and the outer sole proper, and is made from a rubber or plastic material that is characteristic of a high-level shock-absorber. In one example of implementation, the outer sole is made from a cellular material whose elasticity and shock-absorbing properties allow the design of the shock-absorbing element and of the said outer sole as a single part. This shock-absorbing element takes the form of a vertical hollow cylinder that bears upon the base of the outer sole proper, at the level of an annular groove formed in the latter. The inner sole rests on the top edge of the tubular shock-absorbing element.
In this method of implementation, the outer sole into which the shock-absorbing element is incorporated is made from a rubber or plastic material that is characteristic of a high-level shock-absorber. It therefore cannot be a conventional outer-sole material, and this can have drawbacks in relation to resistance to wear or abrasion of the outer sole.